1. Field of the Invention
The present invention relates to a LGF (light guide film) roll-to-roll (R2R) manufacturing method and a structure thereof which is applied to a LCD (liquid crystal display) backlight module. More particularly, the present invention relates to the LGF roll-to-roll manufacturing method utilizing mechanical extrusion and UV curing non-synchronously or synchronously and the structure manufactured thereby.
2. Description of the Related Art
U.S. Pat. No. 7,862,223, entitled “Thin and flexible light guide element,” discloses a thin and flexible light guide element and a manufacturing method thereof. The thin and flexible light guide element comprises: a first optical layer composed of a flexible transparent material; a second optical layer formed on the lower side of the first optical layer and having a light-adjusting structure to change the light path; and a third optical layer formed on the upper side of the first optical layer and having a convex-concave structure to homogenize the light emitted from the first optical layer. The first and second optical layers have different refractive indices.
The second optical layer is formed by a first composition coated on the lower-side surface of the first optical layer. The first composition includes a mixture of a UV curing resin monomer and a photo initiator. Furthermore, the third optical layer is formed in the same way by a second composition coated on the upper-side surface of the first optical layer. The second composition includes an anti-static agent, a UV curing resin, organic particles and an additive. The additive is selected from a thermal setting resin, a thermal plastic resin and a mixture thereof.
Accordingly, the first and second optical layers have relatively different refractive indices. In manufacturing, the second and third optical layers are continuously produced by a series of roll-to-roll (R2R) procedures. Namely, each of the second and third optical layers is separately formed by a curing process on each of the lower-side and upper-side surfaces of the first optical layer.
In order to form the second and third optical layers on the different two sides of the first optical layer, several coating and curing processes are required in different sides. However, the double-side coating and curing processes applied to a single thin film are complex and difficult. Disadvantageously, this results in an increase of the manufacturing cost.
Consequently, there exists a need of providing a simplified method for producing such a thin and flexible light guide element. U.S. Pat. No. 7,862,223 is incorporated herein by reference for purposes including, but not limited to, indicating the background of the present invention and illustrating the state of the art.
As is described in greater detail below, the present invention provides a simplified LGF roll-to-roll manufacturing method and a structure thereof. A first integrated (extruded) microstructure is extruded to form a first surface of an optical layer, and a second microstructure is formed on the optical layer non-synchronously or synchronously in such a way to mitigate and overcome the above problem.